Add. $\begin{aligned} 22& \\ 46&\\ 17&\\ \underline{+21}& \\ \end{aligned}$
Solution: First, let's add $22 + 46$. $$ $$ $$ ${+}$ $$ $$ $$ $$ $$ $$ ${=}$ $$ $$ $$ $$ $$ $$ $$ $$ $22} + {46} = 68$ Now, let's add $68$ to $17$. $$ $$ $$ $$ $$ $$ $$ $$ ${+}$ $$ $$ $$ ${=}$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $68+ {17} =85$ Last, let's add $85$ to $21$. $$ $$ $$ $$ $$ $$ $$ $$ $$ ${+}$ $$ $$ $$ ${=}$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $85+ {21} = 106$ $\begin{aligned} 22& \\ 46&\\ 17&\\ \underline{+21}& \\ 106 \end{aligned}$